Package for a detergent bar

ABSTRACT

The invention provides a planar ( 1 ) stiffener for use in packaging of detergent bars, the stiffener having a machine-direction (MD) and perpendicular thereto a cross-direction (CD), characterised in that said stiffener has a plurality of ribs ( 2 ) along its cross-direction. The stiffeners when used in packaging soap or detergent bars are less prone to deformation along the lateral sides ( 6, 7 ) and edges of the package ( 3 ). This makes the stiffener characteristics more suitable for retaining the envelope wrapped shape of the package to a significant extent until the end consumer point.

FIELD OF INVENTION

The present invention relates to packaging of detergent bars, moreparticularly to packaging of individual detergent or soap bars usingstiffeners.

The invention has been developed primarily for use in packaging ofdetergent bars and will be described hereinafter with reference to thisapplication. However, it will be appreciated that the invention is notlimited to this particular field of use.

BACKGROUND AND RELATED ART

Any discussion of the prior art throughout the specification should inno way be considered as an admission that such prior art is widely knownor forms part of the common general knowledge in the field.

Detergent bars, especially soap bars, are made in various fancifulshapes to attract consumers. Soap bars that essentially are rectangularcan readily be wrapped in conventional packages having a combination ofa stiffener and a wrapper. The stiffener is included to provideadditional strength to the package. The soap bar normally fully supportsthe wrapper as the wrapper takes the shape of the soap bar. However,when the soap bar is not essentially rectangular, and has curved edges,the package parts usually must provide some of the shape to the package.

An individual bar of soap or detergent after being packaged in a wrapperis then packed in larger cartons before being despatched from thefactories. These larger packs are generally referred to as “CorrugatedCartons for Local Delivery” (CLD). These cartons are then transported inbulk to retailing units. The cartons are generally transported intrucks.

During transportation and storage, the packaged soap bar is subjected tomechanical stress. Therefore, the individual packages undergodeformation and damage at several places before reaching the retailingoutlets. Such deformed packs are not suitable for display and aregenerally not acceptable to consumers too. In packages where stiffenersare included, it is observed that the extent of deformation iscomparatively lesser. However, it has also been observed by the presentinventors that commercially available stiffeners have high stiffnessalong the machine-direction, but comparatively little stiffness alongthe cross-direction thereof, which results in packages or wrappershaving crushed or deformed lateral sides and/or edges. This particularlyis the case in the area of the ends of the soap bar package where thereis a transition from a top, bottom and side surface to the folded endsurfaces.

One way to solve this problem is by using thicker stiffeners, i.e. oneshaving higher grammage. Their benefits would normally be offset by thecorresponding increase in cost. Another way is to use a corrugated sheetof paper as a stiffener. Their use would, however, lead to an increasein the overall bulk of the pack. In addition, stiffeners made ofcorrugated sheets may be prone to tear off at their open corrugatedends, after the package is deformed at the edges.

An attempt has been made in the past to solve this problem.

US 2005/0035008 (Colgate Palmolive) describes a wrapper for a soap barmade from a single sheet of material having gusseted end-folds toprovide increased rigidity to the pack. This is produced by forming thegusseted end-folds where extra reinforcement is desired. The gussetsproduce a three layered structure and act as reinforcement bands thatreduce deformation of the ends of the pack.

As can be seen here, US '008 relates to packages that essentially aim atachieving additional strength by using extra folds of the wrapper whichwould require modification of the process and would also lead to anincrease the cost.

There exists the need for stiffeners having relatively higher stiffnessalong the cross-direction so that deformation of packages along theedges and ends that occur while transportation, storage and handling canbe prevented or reduced.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a stiffener that hasrelatively high stiffness along the cross direction.

Conventional single/multiple ply stiffeners used in envelope wrappedproducts such as soaps and detergent bars, have anisotropic stiffness inmachine-direction (MD) and cross-direction (CD), where the stiffness inmachine-direction is greater than stiffness in cross-direction due tograin direction of the stiffener. The present invention aims atmodifying the cross-direction stiffness by suitable mechanical changesin the stiffener. This makes the stiffener characteristics more suitablefor retaining the envelope wrapped shape of the package to a significantextent until the end consumer point. The present inventors have foundthat planar stiffeners having a plurality of ribs along thecross-direction surprisingly show relatively higher stiffness in thecross-direction, when compared to normal stiffeners. Such stiffenerswhen used in packaging soap or detergent bars would be less prone todeformation along the lateral sides and edges of the package.

SUMMARY OF THE INVENTION

According to an aspect the present invention relates to a planarstiffener for use in packaging of detergent bars, the stiffener having amachine-direction and perpendicular thereto, a cross-direction,characterised in that the stiffener has plurality of ribs along itscross-direction.

Preferably the angle of the ribs with the cross-direction of thestiffener is from 0° to 45°, more preferably it is 0°. Preferably thedistance between the adjacent ribs of the stiffener ranges from 0.5 mmto 2 mm.

According to another aspect the present invention relates to a packagefor a detergent bar comprising a planar stiffener according to the firstaspect of the invention, that surrounds the bar along the longitudinalextent thereof. Preferably the package comprises a wrapper overlayingthe stiffener.

According to another aspect the present invention relates to a packageddetergent bar comprising:

-   -   (i) a detergent bar;    -   (ii) a planar stiffener according to the first aspect of the        invention, and    -   (iii) a wrapper overlaying the stiffener.

According to another aspect the present invention relates to a processfor preparing a planar stiffener according to the first aspect of theinvention, comprising the steps of:

-   -   (i) softening a tensioned sheet of paper, paper board or        polycoated paper by contacting it with a softening agent;    -   (ii) passing the tensioned sheet between a pair of        counter-currently rotating grooved rollers operating under        pressure from 500 psi to 2000 psi to form a plurality of ribs        along the cross-direction of the sheet, the rollers being        disposed one of top of the other;    -   (iii) passing the sheet through a heating zone; and optionally,    -   (iv) cutting the sheet to required size.

According to another aspect the present invention relates to anapparatus for making a planar stiffener according to the inventioncomprising:

-   -   (i) a means for unwinding a sheet of paper, paper board or        polycoated paper;    -   (ii) means for holding the sheet in a tensioned state as it        passes through said apparatus, the means being located on either        sides of a pair of grooved counter-currently rotating rollers        through which the sheet passes in a tensioned state;    -   (iii) a means for spraying softening agent located before the        rollers;    -   (iv) a means for heating the sheet located after the rollers;        and optionally,    -   (v) a means for winding the sheet.

According to another aspect the present invention relates to use of aplanar stiffener according to the first aspect of the invention, inpackaging of a detergent bar.

The term “detergent bar” is used herein to indicate a bar or tablet ofnon-soap or soap-based detergents, which are primarily used for washingclothes, and a bar or tablet of soap, which is used for personalwashing.

The terms “soap” and “detergent” have been used interchangeably in thespecification.

Stiffener

The term planar is used to indicate that the stiffener is essentiallyflat, unlike a sheet of corrugated paper.

Preferably, the stiffener is made of coated or uncoated paper. It mayalso be made of coated or uncoated paper board. It may also be made ofplastic or a laminate of paper and plastic, generally known aspolycoated paper. More preferably, it is made from paper board, coatedon one side with a Polyethylene coating. Polycoated papers areadvantageous as in addition to providing strength, they also prevent orreduce loss of aroma/perfume and volatile components from the packagedbar.

Stiffeners have two directions based on the formation on the paper boardmanufacturing machines. These are known as the machine-direction (MD)and cross-direction (CD). Machine-direction refers to the direction inwhich the paper travels and it has higher stiffness (usually measured inTaber units) as compared to the cross-direction. The cross-direction isperpendicular to the machine-direction.

It is especially preferred that the stiffener is free from memory sothat it does not unfold from a roll on which it was stored and so thatit can be folded around the bar of soap, preferably around the entireperipheral longitudinal surface, of the detergent bar, after which thestiffener will remain in the folded condition so as to define a sleevesurrounding the bar. It is preferred that the stiffener entirelysurrounds the detergent bar along its longitudinal extent, so as todefine a sleeve of the stiffener, housing the detergent bar. It ispreferred that the lateral sides of the bar of soap are not surroundedby the stiffeners, so that the bar can be easily removed for use.

It is preferred that the angle of the ribs with the cross-direction ofthe stiffener is from 0° to 45° and more preferably from 0° to 30°. Itis most preferable that this angle is 0°.

Preferably the distance between two adjacent ribs ranges from 0.5 mm to2 mm. More preferably the distance is 1 mm.

The cross-direction stiffness of the stiffener is from 10 to 40 TaberUnits. Preferably it is from 15 to 30 Taber units.

It is preferred that the grammage of the stiffener is from 90 g/m² to200 g/m², more preferably from 120 g/m² to 170 g/m². It is however mostpreferable to use low grammage stiffeners from 130 g/m² to 150 g/m².However, a higher grammage stiffener can be used if highercross-direction strength is sought.

It is preferred that the thickness of the stiffeners is from 120μ to400μ. However it is preferred that the thickness is from 150μ to 300μ.It is most preferable to use stiffeners having thickness between 250μand 270μ.

The term “ribs” as used herein is meant to include equivalent terms suchas “knurlings”.

It is further preferred that the softening agent is low pressure steam.

It is preferred that the material of construction of the rollers istoughened/hardened steel or stainless steel with or without anti-stickcoating.

Any suitable means of heating can be employed in the heating zone.

Generally, the heating zone has one or more heat radiators. Preferablythe heating means is an electrical heater or an infrared heater.

Wrapper

The wrapper is a film material comprising a paper core coated on eachsurface with a plastics material. However, preferably the wrapper is afilm material which is entirely of plastics material, more preferablythermoplastics material.

The film material of the wrapper preferably has a thickness of from 5 to50 microns.

Preferably, the wrapper, when wrapped around the bar of detergent andstiffener, has edge portions in overlapping relationship with oneanother. This allows those edge portions to be secured to one another.This can be achieved by application of an adhesive between variousrespective opposite surface regions, for example, by coating theadhesive at various regions of the edge portions, folding the wrapperand applying pressure. However, preferably, edge portions are secured toone another by heat sealing so that at least outer layers of the filmmaterial of the wrapper are preferably of heat sealable plasticsmaterial. Moreover, the edge portions are preferably kept free ofprinting material.

Preferably, the film material of the wrapper comprises at least onelayer of a Biaxially Oriented PolyPropylene (BOPP) capable of heatsealing. More preferably the film is a laminate of a Biaxially OrientedPolyPropylene (BOPP) layer with a low density polyethylene film.

Preferred examples of alternative constructions of the wrapper are:

-   -   (a) a laminate of a heat sealable film an internal face of which        may bear print material and between which a laminating, for        example hot melt, adhesive is applied;    -   (b) a special BOPP film which is capable of heat sealing; and    -   (c) a laminate of a PET (Polyethyleneterepthalate), nylon or low        density polyethylene film adhered, for example with a hot melt        adhesive, to a heat sealable film.

A package according to the invention containing a soap bar can beproduced by a method comprising the steps of:

-   folding around at least a longitudinal extent of the bar of soap, a    stiffener, so that it is wrapped laterally around the bar; wrapping    each of the bar of soap and stiffener with a wrapper in a manner    such as entirely to surround each of the bar of soap and stiffener    and to provide overlapping edge portions of the wrapper; and-   adhering together, preferably by heat sealing, at least respective    parts of the overlapping edge portions to secure the wrapper in    position.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 is the front view of an embodiment of a stiffener according tothe invention.

FIG. 2 is the front view of another embodiment of a stiffener.

FIG. 3 is the isometric view of a packaged detergent bar in accordancewith the invention.

FIG. 4 is a schematic of a machine used for making the stiffenersaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In all the figures, like numerals have been used to indicate like parts,components or features.

Referring to FIG. 1, the rectangular stiffener 1 has is plurality ofribs 2 that run parallel to the cross-direction (CD) and perpendicularto the Machine direction (MD), which have been shown with the help ofarrows. The angle of the ribs with the cross-direction of stiffener 1 is0°.

FIG. 2 shows another embodiment of a stiffener 1. The angle of the ribs2 with the cross-direction of the stiffener is 45°.

Referring now to FIG. 3 that shows the isometric view of a packageddetergent bar 3 according to the invention, the bar has longitudinalsides 4 and 5, and lateral sides 6 and 7. The wrapper 8 of the bar isfolded over itself along the edges and is adhesively bonded to definethe lateral flap 9. A portion of the wrapper is cut-away to show theplurality of ribs 2 on the stiffener 1 that lies beneath the wrapper 8.

Referring now to FIG. 4 that shows a schematic of an apparatus and aprocess of making the planar stiffeners having plurality of ribs alongits cross-direction, a roll of normal (un-ribbed) stiffener made ofpaper, paper board or polycoated paper is loaded on the mandrel of theunwinder 10 and the same is unwound and pulled by a motor (14)controlled pair of rubber pinch roller 11 a and a steel roller 12 a.This pair keeps the sheet in a tensioned state. The intended frictionaltraction force to create the required pull is achieved by frictioncoefficient of the pair of rollers 11 a and 12 a, which is decided bythe material of construction of the roller pair and normal force onrollers generated by the spring 13 a. The sheet so unwound then passesthrough humidifying arrangement 15 a and 15 b where low-pressure steamis sprayed on the sheet, which acts as the softening agent. Thisprepares the sheet for ribbing. Ribbing is achieved by a speciallyprofiled and spring loaded pressurized pair of counter-currentlyrotating grooved rollers 16 a and 16 b, pressurized by cylinder 17. Thetangential speed of these rollers is decided by a separate driving gearpair (not shown). The stiffener then enters a heating zone where a pairof heaters 18 a and 18 b supply intense heat by use of Infraredradiators to dry-up and stabilize the deformation added to thestiffeners surface. The next pair of pinch roller 11 b and steel roller12 b pulls the stiffener gently without causing any appreciable stretch,which is achieved by motor 19 controlled feedback loop which is part ofthe process. This loop monitors and controls the take-up velocity of thepair of rollers. Finally the winder 20 operates on tension controlprinciple and tightly rewinds the stiffener. This is then sent to thewrapping machines. The entire operation is controlled with the controlmeans 21.

The invention will now be explained with the help of followingnon-limiting examples.

EXAMPLES

The Taber stiffness values of Stiffeners made according to theinvention, as well as comparative stiffeners, i.e. without ribs weremeasured. The values have been compiled in tables 1-4 below. In all thetables, MD and CD represent the stiffness in Taber units of theStiffeners in the Machine direction and Cross direction respectively.

TABLE 1 130 g/m² stiffeners (without ribs) PLAIN MD CD POLYCOATED MD CDSAMPLE-1 17 8 SAMPLE-1 13 8 SAMPLE-2 18 6 SAMPLE-2 18 8 SAMPLE-3 20 6SAMPLE-3 15 6 SAMPLE-4 13 8 SAMPLE-4 15 6 SAMPLE-5 15 8 SAMPLE-5 15 6AVERAGE 16.6 7.2 AVERAGE 15.2 6.8 *Average Thickness of 130 g/m²stiffeners: PLAIN - 196μ; POLYCOATED - 208μ

TABLE 2 150 g/m² stiffeners (without ribs) PLAIN MD CD POLYCOATED MD CDSAMPLE-1 35 10 SAMPLE-1 25 13 SAMPLE-2 25 17 SAMPLE-2 28 10 SAMPLE-3 3520 SAMPLE-3 25 12 SAMPLE-4 25 20 SAMPLE-4 28 15 SAMPLE-5 25 17 SAMPLE-525 13 AVERAGE 29 16.8 AVERAGE 26.2 12.6 *Average Thickness of 150 g/m²stiffeners: PLAIN - 233μ; POLYCOATED - 239μ

TABLE 3 175 g/m² stiffeners (without ribs) PLAIN MD CD POLYCOATED MD CDSAMPLE-1 40 25 SAMPLE-1 37 15 SAMPLE-2 40 25 SAMPLE-2 28 15 SAMPLE-3 4025 SAMPLE-3 33 18 SAMPLE-4 38 23 SAMPLE-4 30 15 SAMPLE-5 42 20 SAMPLE-533 18 AVERAGE 40 23.6 AVERAGE 32.2 16.2 *Average Thickness of 150 g/m²stiffeners: PLAIN - 277μ; POLYCOATED - 283μ.

Stiffness Values of Stiffeners According to the Invention.

TABLE 4 130 g/m² polycoated stiffeners SAMPLE MD AVERAGE CD AVERAGESAMPLE-A 30 30 20 20 (500 psi) 40 20 25 20 25 20 SAMPLE-B 20 24 10 12.5(400 psi) 30 15 30 15 15 10 SAMPLE-C 15 15 10 12.5 (300 psi) 15 10 15 1015 20

The average thickness of 130 g/m² (Ribbed) stiffeners was 260μ. Distancebetween adjacent ribs was 1 mm. The angle of ribs was 0° with respect tothe cross direction of the stiffener. The pressure of the groovedrollers through which the stiffeners were passed has been indicated inbrackets.

The stiffeners were made of Rough cartridge board paper which can beobtained from Andhra Pradesh Paper Mills, Star Paper Mills or CenturyPaper Mills.

The paper was then extrusion coated with Polyethylene (10μ) by processesgenerally known in the art.

Thus it can be readily appreciated that the Cross Direction stiffness ofthe Stiffeners according to the invention (table 4, Sample-A) isrelatively higher than stiffeners of table 1 to 3. It can also beappreciated that the stiffness increases as the pressure is increased.This therefore means that at a lower grammage, it is possible to have astiffener that has relatively higher Taber stiffness in thecross-direction.

It will be appreciated that the illustrated examples, provide for astiffener that has relatively high stiffness along the cross direction.

Although the invention has been described with reference to specificembodiments, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms.

1. A planar stiffener for use in packaging of detergent bars, thestiffener having a machine-direction and perpendicular thereto across-direction, characterised in that said stiffener has plurality ofribs along its cross-direction.
 2. A planar stiffener as claimed inclaim 1 wherein the angle of said ribs with the cross-direction of saidstiffener is from 0° to 45°.
 3. A planar stiffener as claimed in claim 2wherein said angle is from 0° to 30°.
 4. A planar stiffener as claimedin claim 3 wherein said angle is 0°.
 5. A planar stiffener as claimed inany one of the preceding claims, wherein the distance between theadjacent ribs ranges from 0.5 mm to 2 mm.
 6. A planar stiffener asclaimed in claim 5 wherein said distance is 1 mm.
 7. A planar stiffeneras claimed in any one of the preceding claims wherein thecross-direction stiffness of said stiffener is from 10 to 40 TaberUnits.
 8. A planar stiffener as claimed in claim 7 wherein saidstiffness is from 15 to 30 Taber units.
 9. A planar stiffener as claimedin any one of the preceding claims, wherein the grammage of saidstiffener is from 90 g/m² to 200 g/m².
 10. A planar stiffener as claimedin claim 9 wherein said grammage is from 120 g/m² to 170 g/m².
 11. Aplanar stiffener as claimed in claim 10 wherein said grammage is from130 g/m² to 150 g/m².
 12. A planar stiffener as claimed in any one ofthe preceding claims, wherein the thickness of said stiffener is from120μ to 400μ.
 13. A planar stiffener as claimed in claim 12 wherein saidthickness is from 150μ to 300μ.
 14. A planar stiffener as claimed in anyone of the preceding claims, wherein said stiffener is made of paper,paper board, or polycoated paper.
 15. A package for a detergent barcomprising a planar stiffener as claimed in any one of the precedingclaims that surrounds said bar along longitudinal extent thereof.
 16. Apackage as claimed in claim 15 wherein said package comprises a wrapper,overlaying said stiffener.
 17. A packaged detergent bar comprising: (i)a detergent bar; (ii) a planar stiffener as claimed in any one of thepreceding claims 1 to 14, and (iii) a wrapper overlaying said stiffener.18. A process for preparing a planar stiffener as claimed in any one ofthe preceding claims 1 to 14, comprising the steps of: (i) softening atensioned sheet of paper, paper board or polycoated paper by contactingit with a softening agent; (ii) passing said tensioned sheet between apair of counter-currently rotating grooved rollers operating underpressure from 500 psi to 2000 psi to form a plurality of ribs along thecross-direction of said sheet, said rollers being disposed one of top ofthe other; (iii) passing said sheet through a heating zone; andoptionally, (iv) cutting said sheet to required size.
 19. A process asclaimed in claim 18 wherein softening agent said is low pressure steam.20. A process as claimed in claim 18 or 19 wherein said heating zonecomprises one or more heat radiators.
 21. An apparatus for making aplanar stiffener as claimed in any one of the preceding claims 1 to 14comprising: (i) a means for unwinding a sheet of paper, paper board orpolycoated paper; (ii) means for holding said sheet in a tensioned stateas it passes through said apparatus, said means being located on eithersides of a pair of grooved counter-currently rotating rollers throughwhich said sheet passes in a tensioned state; (iii) a means for sprayingsoftening agent located before said rollers; (iv) a means for heatingsaid sheet located after said rollers; and optionally, (v) a means forwinding said sheet.
 22. An apparatus as claimed in claim 21 wherein themeans for holding said sheet in a tensioned state includes two pairs ofrollers, each said pair comprising a rubber pinch roller and a steelroller.
 23. An apparatus as claimed in claim 21 wherein said softeningagent is low pressure steam.
 24. An apparatus as claimed in claim 21wherein said means for heating comprises one or more heat radiators. 25.Use of a planar stiffener as claimed in any one of the preceding claims1 to 14 in packaging of a detergent bar.
 26. A package substantially asherein described with reference to the accompanying examples andfigures.
 27. A planar stiffener substantially as herein described withreference to the accompanying examples and figures.
 28. A processsubstantially as herein described with reference to the accompanyingexamples and figures.
 29. An apparatus substantially as herein describedwith reference to the accompanying figures and examples.
 30. A packageddetergent bar substantially as herein described with reference to theaccompanying figures.